Without any good sources to quote, I'd say "no." Studded Leather is modified by material the same way that leather is...in my games. A specific ruling on which armors can be modified by which special materials is, as far as I know, non-existent, we have only the "metal or non-metal" assumption.
If this is for YOUR game, I recommend deciding (as a once-and-for-all ruling) how "mixed" armors should be handled.
If this is for you as a player, talk to your GM.
If this is for PFS, I'm sorry, I can't help you.
Studded leather has enough metal to prevent a druid from wearing it, does it have enough metal to grant DR 1/- if the studs were adamantine?
Ya know, now that you said it, that's weird.
Generally, no. The object in question needs to be primarily- or at least the important parts, in the case of metal bladed weapons- made of metal to benefit from a special metal. Similarly, the object needs to be made mostly of wood to benefit from the darkwood materials. Hence, a alchemical silver tipped spear would benefit from the special steel (the important part*), but a pistol with dark handles would not benefit from that special materials.
* Yes, I know. You could replace the wooden pole with darkwood
* Yes, I know. You could replace the wooden pole with darkwood
There's still an advantage to doing so. It ups the hardness of the weapon overall, in that hafted weapons use the hardness of the haft for defending against sunder attempts. So anything that ups your hardness/hp is good. So a bardiche with an adamantine blade and darkwood haft get's the benefits of both (Adamantine when attacking, darkwood when defending).